China
Africa
Explore chapters and articles related to this topic
Case Study: A Crashing Limb: Thinking about where Failure will Happen
Published in Todd Conklin, Pre-Accident Investigations, 2019
The meteorologist on the news the night before had said that it would be a small storm with a chance of showers. I found out from my neighbor that what we had experienced was a bizarre phenomenon called a “microburst.” A microburst is a severe, localized wind blasting down from a thunderstorm. A dramatic wind shear is erratic and virtually unpredictable. A microburst only affects a small area—less than 2.5 square miles—and it happened at my house. The weatherman predicted a small storm and a deluge.
Force-System Resultants and Equilibrium
Published in Richard C. Dorf, The Engineering Handbook, 2018
one has defined a simplified version of a meteorological phenomenon called a microburst. A microburst is a downburst that is confined to a relatively small area, and is characterized by a massive downward air mass movement that disperses radially near the ground. An intense microburst can be extremely hazardous to aircraft when landing or taking off [Wingrove and Bach, 1989]. Figure 194.2 represents a vertical
An analogy-based method for strong convection forecasts in China using GFS forecast data
Published in Atmospheric and Oceanic Science Letters, 2020
Na LI, Lingkun RAN, Baofeng JIAO
In this paper, an ‘analogy’ is defined as a past prediction that matches the strong-convection-occurrence environment of the current forecast. The parameters involved in describing the basic environment producing these phenomena are: vertical velocity at the surface (Wsfc) and 850 hPa (W850), horizontal divergence at the surface (DIVsfc) and 850 hPa (DIV850), divergence of Q-vector at the surface (DIVQsfc) and 850 hPa (DIVQ850), horizontal divergence of moisture flux at the surface (DIVQFsfc) and 850 hPa (DIVQF850), precipitable water (PW), lifting index (LI), convective available potential energy (CAPE), convective inhibition (CIN), K-index, convective stability index (IC), conditional instability index (IL), conditional convective instability index (ILC), deep convective index (DCI), microburst day potential index (MDPI), total temperature (TT), severe weather threat index (SWEAT), energy helicity index (EHI), stability and wind shear index for thunderstorms in Switzerland (SWISS), wind index (WINDEX), bulk Richardson number (BRN), and storm strength index (SSI). These parameters describe different aspects of the atmospheric characteristics. Wsfc, W850, DIVsfc, DIV850, DIVQsfc, and DIVQ850 indicate the lifting conditions for convection. DIVQFsfc, DIVQF850, and PW reflect the humidity of the air. LI, CAPE, MK, IC, IL, and ILC describe the instability of the atmosphere. MDPI, SWEAT, and WINDEX are empirical parameters for strong weather, such as microbursts, gusts, hail, and so on. With these parameters as the criteria, the more their values approach one another between the two different times, the greater the analogy between their atmospheres. To incorporate all the parameters into the analogy-detection method, following Delle Monache et al. (2011), a formula measuring the analogy for a given location is defined as follows:
Droplet evaporation characteristics of hydrogenated biodiesel-ethanol-diesel ternary fuel
Published in Combustion Science and Technology, 2023
Yue Yu, Deqing Mei, Yaping Gao, Jiawei Qi, Chuanfang Zhang
Evaporation is the phase change of a substance from a liquid to a gas state. The evaporation of droplets and the fuel-air distribution in the chamber are key factors to fulfill effective combustion. The volatile components in droplets may give rise to microbursts during evaporation (Banerjee 2013). In order to apply the bubble microburst in droplet evaporation in a rational way to obtain good fuel-gas mixing quality and subsequent clean and efficient combustion performance, an in-depth understanding of the droplet evaporation and internal bubble movement is necessary (Rao, Karmakar, and Basu 2018). The formation of bubbles inside the droplet is influenced by the nucleation of volatile components and the rapid warming of light volatile components (Rao, Karmakar, and Basu 2018). Therefore, light volatile components such as ethanol can facilitate fuel evaporation (Yang et al. 2021). Furthermore, components with different volatilities, such as biodiesel, ethanol, and diesel, can have important effects on their evaporation characteristics (Mei et al. 2020). To understand the interaction of different components in the evaporation (Qubeissi et al. (2021) applied a mixed evaporation model to simulate the evaporation of a single droplet of gasoline as well as multi-component fuels and found that the lighter hydrocarbon components of each group evaporated preferentially, and the evaporation of aromatic hydrocarbon compounds lagged behind that of other hydrocarbon compounds under similar molecular weight conditions. Ra and Reitz, constructed a vaporization model to calculate the evaporation of multi-component fuel droplets and sprays under various ambient temperatures and droplet temperatures (Girin 2017). Found that the interfacial instability after microbursts increased the evaporation rate of liquid fuels (Hashimoto et al. 2015). Investigated the evaporation characteristics of palm methyl ester droplets at high ambient temperatures and revealed that the droplet lifetime of all fuels was decreased with increasing ambient temperature (Keller, Bader, and Hasse 2013). Investigated the heat and mass transfer processes within the droplet and found that, especially at higher temperatures, mass transfer limitations significantly reduced the difference in effective volatility.